Ndour N. Y. B., Baudoin Ezekiel, Guisse A., Seck M., Khouma M., Brauman Alain. (2008). Impact of irrigation water quality on soil nitrifying and total bacterial communities. Biology and Fertility of Soils, 44 (5), p. 797-803. ISSN 0178-2762.
Titre du document
Impact of irrigation water quality on soil nitrifying and total bacterial communities
Ndour N. Y. B., Baudoin Ezekiel, Guisse A., Seck M., Khouma M., Brauman Alain
Source
Biology and Fertility of Soils, 2008,
44 (5), p. 797-803 ISSN 0178-2762
Disturbance induced by two contrasting irrigation regimes (groundwater versus urban wastewater) was evaluated on a sandy agricultural soil through chemical and microbial analyses. Contrary to wastewater, groundwater displayed very high nitrate contents but small amounts of ammonium and organic matter. Despite these strong compositional shifts, soil organic carbon and nitrogen, nitrate and ammonium contents were not significantly different in both types of irrigated plot. Moreover, neither microbial biomass nor its activity, determined as fluorescein diacetate hydrolysis activity, was influenced by irrigation regimes. Bacterial community structure, assessed by denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA fragments, was also weakly impacted as molecular fingerprints shared an overall similarity of 85%. Ammonia-oxidizing bacterial community (AOB) was monitored by DGGE of the functional molecular marker amoA gene (alpha subunit of the ammonia monooxygenase). Surprisingly, no amoA signals were obtained from plots irrigated with groundwater, whereas signal intensities were high in all plots under wastewater. Among the last, compositional shifts of the AOB community were weak. Overall, impact of irrigation water quality on soil chemistry could not be evidenced, whereas effects were low on the total bacterial compartment but marked on the AOB community.
